My first choice would be Chitoge because she seems to have more in connection to the promise girl thanks to the info from her Mom and Dad

Spoiler Alert! Click to show or hide

her mother told her it was because of Raku she started wearing ribbons and her dad told her she used to have brown or hazel eye color (the colors of the promise girl) before it turned blue

Onodera to me seems unlikely a little bit because she is what he DREAMS of being his promise girl and we all know in manga and anime sometimes you don't always end up with the character you want.

To be honest in my opinion for any of the other three to end up with Raku would mean ALL of them would end up with Raku meaning a harem. Why ? Well no other Character is not going to win against the main heroines of the story being Chitoge and Onodera.

Well Raku does like Onodera right now he did say so himself. If he were to pick anybody else what was the point of saying he liked Onodera all those times. Besides we probably won't be seeing him get with anybody for a really long time.

Road A: Super obvious Chitoge route - Seriously, she's main girl.
Road 2: Everyone- Raku goes to Vegas and wins the lottery
Road Triangle: Himself (AKA Nobody): Raku is as indecisive as a girl with ADHD looking for shoes at your local mall, and ends up picking nobody and dies a lonely life by himself...

These series rarely tread new ground. Since Chitoge is the key female, she is the obvious choice. I personally would like Onodera, but I'll be the first to admit she hasn't gotten anywhere near equal focus or character development as Chitoge, so her winning at this point would be really poor writing.

Onodera's character development just doesn't extend much past "I like Raku" and "I suck at cooking". Hell, her younger sister has had more development than she has at this point...